// Allocate an external port and map it to the interface
func AllocatePort(id string, port nat.Port, binding nat.PortBinding) (nat.PortBinding, error) {
var (
ip = defaultBindingIP
proto = port.Proto()
containerPort = port.Int()
network = currentInterfaces.Get(id)
)
if binding.HostIp != "" {
ip = net.ParseIP(binding.HostIp)
if ip == nil {
return nat.PortBinding{}, fmt.Errorf("Bad parameter: invalid host ip %s", binding.HostIp)
}
}
// host ip, proto, and host port
var container net.Addr
switch proto {
case "tcp":
container = &net.TCPAddr{IP: network.IP, Port: containerPort}
case "udp":
container = &net.UDPAddr{IP: network.IP, Port: containerPort}
default:
return nat.PortBinding{}, fmt.Errorf("unsupported address type %s", proto)
}
//
// Try up to 10 times to get a port that's not already allocated.
//
// In the event of failure to bind, return the error that portmapper.Map
// yields.
//
var (
host net.Addr
err error
)
hostPort, err := nat.ParsePort(binding.HostPort)
if err != nil {
return nat.PortBinding{}, err
}
for i := 0; i < MaxAllocatedPortAttempts; i++ {
if host, err = portMapper.Map(container, ip, hostPort); err == nil {
break
}
// There is no point in immediately retrying to map an explicitly
// chosen port.
if hostPort != 0 {
logrus.Warnf("Failed to allocate and map port %d: %s", hostPort, err)
break
}
logrus.Warnf("Failed to allocate and map port: %s, retry: %d", err, i+1)
}
if err != nil {
return nat.PortBinding{}, err
}
network.PortMappings = append(network.PortMappings, host)
switch netAddr := host.(type) {
case *net.TCPAddr:
return nat.PortBinding{HostIp: netAddr.IP.String(), HostPort: strconv.Itoa(netAddr.Port)}, nil
case *net.UDPAddr:
return nat.PortBinding{HostIp: netAddr.IP.String(), HostPort: strconv.Itoa(netAddr.Port)}, nil
default:
return nat.PortBinding{}, fmt.Errorf("unsupported address type %T", netAddr)
}
}
